It is important to calculate the number of the objects within a certain regional space to manage the objects. If the number of people in the entrances and exits of come locations, such as stations, stores, department stores and concerts, can be real-timely calculated, it is helpful to monitor and control the crowds timely in these locations so as to reduce the concern of the fire security. For example, calculating the livestock at the entrance channel in the animal farm is helpful to manage the movement of the livestock. For another example, calculating the finished or semi-finished products through a specific gateway at the product manufacturing line in the factory is helpful to manage the production of the product.
In general, the statistics of the population flow can be applied in an enclosed area and an open area. The calculated device usually configures at the entrance and the exit of the enclosed area such as a library, a museum, an exhibition center, a store, a public transportation, etc. It is typically difficult to accurately estimate the population for the open area such as a parade, an election rally field, a night market, a square, etc. The population density of a small area is usually calculated by taking an aerial photograph and then estimating the number of the people in the large-scale specific area according to the aerial photograph.
For people counting as an example, a radar sensor, a color camera, an ultrasonic sensor and an infrared sensor can detect the number of people entering and leaving a regional space, except determining the number of the crowd one-by-one artificially by the naked eye. The radar sensor uses a Doppler effect to detect moving objects, to estimate the moving rate and direction of the objects by transmitting and receiving the frequency of the electromagnetic of the radar sensor, and then to calculate the number and the flow of the objects via the received wavelength and frequency. However, the disadvantage of the radar sensor is that it is not easy to calculate the number of the objects accurately when the number of crowd is too many. Although the color camera has smaller masking effect when the two or more objects closing to each other and can also calculate the number of more objects passing through the detecting area at the same time, it is easily affected by the changes of the ambient light, which causes the captured foreground data being incorrect, thereby affecting the correctness of the counting results. The infrared sensor and the ultrasonic sensor can not count the objects correctly when the objects are too much or the appearance of a shelter. Therefore, it is important to improve the counting of the objects number in the regional space for managing the objects and the regional space.
It is therefore attempted by the applicant to deal with the above situation encountered in the prior art.